The Features of Hydrochemical Anomaly Precursor of Chaozhou Well in Guangdong Province

According to twenty four years hydrochemical monitoring data of Chaozhou well in Guangdong Province,we have found the feature of hydrochemical anomaly precursor before the moderate and strong earthquakes.The results show that hydrochemical precursor for moderate earthquakes is short-term and impending anomaly,but the one for strong earthquakes is long-term anomaly.It's also indicated that the forecasted epicenter is larger and the forecasted magnitude is also larger for the same duration of the anomaly.For the abnormal pattern contract,the forecasted epicenter is smaller than the anomaly range and the velocity of variation is larger.